Climate change has predominantly been studied in the context of larger, long-lived species with low reproductive rates. However, researchers from the German Primate Center – Leibniz Institute for Primate Research, in collaboration with colleagues from the University of Zurich, have turned their attention to the often overlooked smaller species with high reproductive rates, focusing on the mouse lemurs of Madagascar. These tiny creatures, known for their ability to adapt to changing environmental conditions, could provide critical insights into the impact of climate change on biodiversity in the tropics.
Mouse lemurs thrive in the forests of Madagascar, where they depend on the five-month rainy season to produce offspring and build up a fat reserve to endure the cool dry season when food becomes scarce. But with the rainy season growing drier and the dry season warmer due to climate change, can mouse lemurs continue to adapt and survive? The researchers’ long-term data analysis suggests that climate change is causing significant destabilization in mouse lemur populations, putting them at an increased risk of extinction.
Claudia Fichtel and Peter Kappeler from the German Primate Center have been studying lemurs in Madagascar for many years, compiling an invaluable data set that spans 26 years, from 1994 to 2020. Their work has centered on the demographic structure of a mouse lemur population at the DPZ research station in Madagascar. During the same period, climate data revealed a trend of increasingly drier rainy seasons and warmer dry seasons in the region.
In collaboration with their University of Zurich colleagues, Fichtel and Kappeler analyzed the data and discovered an alarming correlation between climate change and the stability of the mouse lemur population. They observed a rise in mortality rates alongside increasing reproductive rates in the lemurs.
“These opposing trends have prevented a collapse of the mouse lemur population, but have nevertheless led to a destabilization of the population, as the already fast life cycle of the animals has been further accelerated,” explained Fichtel.
Mouse lemurs have been living on Madagascar for millions of years. The exact time of their arrival on the island is challenging to pinpoint, but fossil and genetic evidence suggests that lemurs have inhabited Madagascar for at least 50 million years. The ancestors of modern lemurs likely reached Madagascar by rafting on vegetation mats from mainland Africa, after which they diversified into the many different lemur species we see today, including mouse lemurs.
This fluctuation in population size, driven by climate change, poses a significant threat to the survival of mouse lemurs and could ultimately result in the extinction of the species. Peter Kappeler notes that “even an animal species that is supposedly able to adapt easily to changing environmental conditions thanks to a high reproductive rate is threatened in its survival by climate changes.” This is particularly concerning, as lemurs are endemic to Madagascar and are considered the world’s most endangered mammals.
Claudia Fichtel emphasizes the importance of incorporating demographic stability data when assessing the extinction risk of a species, although she acknowledges that such long-term observations are not yet available for many animal species. The researchers’ findings serve as a stark warning of the potential biodiversity losses in the tropics due to climate change, even among species previously believed to be adaptable to environmental shifts.
The study is published in the journal Proceedings of the National Academy of Sciences.
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